Trans-1-chloro-3,3,3-trifluoropropene (HCFC-1233zd E-isomer) has physical properties, including a boiling point of 20° C., which makes it attractive for certain applications such as foam blowing. The higher boiling point of the cis- or Z-isomer (bp 40° C.) makes it especially desirable not only for foam blowing applications but for solvent applications as well. However, the known procedures for making HCFC-1233zd, all afford only the trans-isomer. Currently there is no known procedure for making exclusively or even primarily the cis-isomer.

Although, the formation of cis-CF3CH═CHCl is reported by Kamil et al., Inorg. Chemistry, 1986, 25, 3760, the product in fact is the trans-isomer—as confirmed by NMR spectroscopy and boiling point. Similarly, dehydrofluorination of 3-chloro-1,1,1-trifluoro-3-iodopropane was reported by Hazeldine, J. Chem. Soc., 1953, 1199-1204, to afford cis-1-chloro-3,3,3-trifluoroprpene, but again, the actual product is the trans isomer with a boiling point of 20° C.
Thus, there continues to be a need for a suitable process to make the cis-isomer of 1-chloro-3,3,3-trifluoropropene for use in various applications. The present invention meets that need.